Inhibition of sucrose intake by continuous celiac, superior mesenteric, and intravenous CCK-8 infusions

Two experiments compared the potency of continuous infusions of cholecystokinin octapeptide (CCK-8) for reducing sucrose intake when administered into abdominal arteries or the jugular vein. Adult, male Sprague-Dawley rats received 22-min infusions of saline or several doses of CCK-8. Sucrose was available for 20 min, beginning 2 min after onset of infusions. In the first experiment, intraceliac CCK-8 in doses of 50, 125, and 312 ng produced significant reductions in intake, but no dose affected intake when administered into the jugular vein. In experiment 2, only the highest dose, 312 ng, suppressed intake when infused into the superior mesenteric artery, and jugular infusions were again ineffective. Behavioral observations indicated that intra-arterial CCK-8 had no affect on feeding within the first several minutes of test meals but accelerated the subsequent decline in incidence of feeding. These results suggest that receptors involved in cholecystokinin satiety are widely distributed within the gastrointestinal tract.

Irradiances of spectral lines in mercury pencil lamps

The irradiancesof 37 spectral lines emitted bymercury pencil-type lamps were measuredby comparison with calibrated continuum sources. The lines span the region 230-590 nm. For the 14 most prominent lines the absolute irradiances should be useful for radiometric calibrations at an uncertainty level of ~15% 195% confidence2. The ratios of the irradiances for this same group of lines are significantly more reproducible; they should be useful at an uncertainty level of ~10%.

Structure-function relationships of the erythropoietin molecule

The tertiary structure of erythropoietin (EPO) remains to be elucidated by X-ray crystallography. Although the amino acid sequence of EPO is known, the specific features that confer its biological activity are not well understood. In order to study the structure-function relationships of EPO by in vitro mutagenesis, we have used the vector pGEX-2T to express human and murine EPO fused to the carboxyl terminus of glutathione S-transferase (GST) in E. coli. The fusion proteins were the predicted size (46 kDa) by SDS-PAGE. GST-huEPO eluted from glutathione-agarose using reduced glutathione (GSH) was tested by radioimmunoassay and in a mouse spleen cell assay (MSCA). Dose-response curves parallel to recombinant human EPO (rHuEPO) were obtained in both assays. The ratio of immuno- to bioactivity was 4.7:1. Thus the presence of the 26 kDa GST protein at the end terminus of EPO does not abrogate biological activity. GST-mEPO also gave dose-response curves parallel to rHuEPO in the MSCA but not in the RIA. The wild-type murine and three mutant GST-EPO fusion proteins (166 Des-Arg, Glu 159-->Val, and Arg 163-->Glu) were tested in the MSCA and assayed for GST activity. The ratio of bioactivity to enzyme activity for the Arg 163-->Glu mutant was approximately one third of the value obtained for each of the other fusion proteins, indicating that arginine at 163 is functionally important for EPO activity. The availability of these human and murine gene constructs in pGEX should facilitate site-directed mutagenesis and permit detailed studies of the structure-function relationships for the two erythropoietins.

Granulocyte and granulocyte-macrophage colony-stimulating factors in cord and maternal serum at delivery

Impaired neutrophil responses contribute to the neonate's increased susceptibility to infection. Because granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) enhance granulocyte and macrophage number and function, their use in the management of neonatal sepsis may be beneficial. Little is known about the endogenous levels of G-CSF and GM-CSF. In adults, raised values for G-CSF, but not GM-CSF, have been demonstrated in patients with infection, and conflicting data has emerged regarding CSF levels in neonates. We have used an ELISA to measure maternal and cord serum G-CSF and GM-CSF at the time of delivery, with gestational age between 25 and 42 wk. In mothers, an inverse linear relationship between gestational age and GM-CSF levels (p = 0.049) was found, but no association with G-CSF levels was observed. In neonates, a quadratic association was found between GM-CSF levels and gestational age (p = 0.019), whereas G-CSF levels showed an inverse linear association (p = 0.015). In addition, an association was found between maternal and cord GM-CSF (p = 0.007) but not G-CSF levels in paired samples. The effect of gestational age on the cytokine levels could not be explained by the white cell count, the absolute neutrophil count, pregnancy-induced hypertension, or the presence of infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Informal carers: a Marxist analysis of social, political, and economic forces underpinning the role

Increasingly, families are being called to provide care to their elderly family members. Nursing has an important role to play in enabling families to assume such responsibilities. In this article, however, it is argued that nursing needs to examine its goals for nursing care and approaches to care delivery in their broader social, political, and economic context. Marxist theory is introduced and used to raise questions about taken-for-granted aspects of nursing practice and trends in health policy as they relate to family carers for the elderly. The article specifically examines assumptions about family, women, and household economies that are inherent in traditional nursing theory. It is argued that nursing needs to move its focus of action beyond work at the individual and family level to include work at system and policy levels. To do so, nursing must examine theoretical perspectives that enable such an inquiry into practice.

Hypobaric hypoxia: a method for testing bioreductive drugs in vivo

Hypobaric hypoxia has been used to induce tumor hypoxia for in vivo comparison of the anti-tumor effects of the bioreductive agents SR 4233 (3-amino-1,2,4-benzotriazine-1,4-dioxide), RSU 1069 (1(2-nitro-1-imidazolyl)-3-aziridino-2-propanol), and Nitromin (methylbis(2-chloroethyl)amine N-oxide). BDF mice bearing the T50/80 mammary carcinoma were treated with these agents over a range of doses under normobaric (oxic) and hypobaric (hypoxic) conditions. The time taken for the tumor to double treatment volume (volume doubling time) was used as a measure of anti-tumor effect. Volume doubling time was plotted against log dose and dose response curves were fitted. A dose enhancement ratio (the ratio of drug doses required to give an equivalent anti-tumor effect under oxic and hypoxic conditions) was determined. The dose enhancement ratios for SR 4233 and RSU 1069 were 8.8 and 8.5, respectively, showing that these agents had an equivalent and substantial enhancement of their cytotoxicity when combined with hypobaric hypoxia. For Nitromin, no significant dose response effect was obtained under oxic conditions precluding the calculation of the dose enhancement ratio. SR 4233 was found to have increased systemic toxicity when combined with hypobaric hypoxia, suggesting that it is more readily activated than the other drugs tested. This in vivo test system will allow determination of the dose enhancement ratio for novel bioreductive agents and facilitate their comparison.

Normal unstimulated lymphocytes produce granulopoietic inhibitory activity

Normal unstimulated lymphocytes cocultured with normal bone marrow will inhibit day-7 colony- forming units in culture. We have shown that this phenomenon has a molecular basis and attempted to characterize it further. Using specific assays and neutralizing monoclonal antibodies we have found that this granulopoietic inhibitory activity (GIA) is not due to alpha- or gamma-interferon, tumor necrosis factor, or acidic or basic isoferritins. Biochemical studies suggest that it is a glycoprotein with a molecular weight greater than 100,000 daltons. It appears to act on cells in S phase, although it may not be S-phase specific. GIA represents a novel inhibitor that merits further investigation.

The proliferative activity of B-chronic lymphocytic leukaemia lymphocytes prior to and after stimulation with TPA and PHA

The proliferative activity of B-CLL lymphocytes from 10 patients was investigated both prior to and after stimulation with TPA and PHA. The analysis of cell cycle-associated features such as BrdU incorporation and the expression of the nuclear proliferation-associated antigen, Ki-67, together with the phenotypic profile of the cells, was performed using double colour immunofluorescent methods. The unstimulated B-CLL cells represented a homogeneous population with the same cell cycle position (G0) as resting peripheral blood lymphocytes. After TPA stimulation 22.7% of the lymphocytes were found in G1, 9.4% in S + G2/M and 13.4% in post-M. PHA stimulation induced a greater proportion of cells in G1, i.e. 35% and 17.8% into S + G2/M and 13.4% into post-M. Double colour immunofluorescence was able to demonstrate that in TPA cultures the majority of the stimulated lymphocytes originated from the malignant clone. Evidence of B-CLL lymphocyte proliferation using double colour labelling with BrdU and Ig kappa and/or Ig lambda showed that a small minority of B-CLL lymphocytes were stimulated into S + G2/M phases of the cell cycle. PHA was also capable of inducing a small proportion of B-CLL cells into mitosis although this proportion of cells was smaller compared to the TPA-stimulated lymphocytes.

Effect of recombinant human erythropoietin on anemia caused by a murine mammary carcinoma

CA NT is a transplantable murine mammary carcinoma that causes progressive anemia accompanied by granulocytosis and splenomegaly. Serum erythropoietin (Epo) levels, as measured by RIA, did not become elevated in anemic tumor-bearing mice; there was no correlation between hematocrit and serum Epo levels. Treatment with recombinant human (rHu) Epo prevented anemia in tumor-bearing mice when given in large doses, commencing on days 3-5 of tumor growth. Recombinant human Epo-treated mice had smaller spleens than controls. When treatment commenced on day 7, the development of anemia was retarded but not completely prevented. Treatment commenced on day 14 was less effective. This study demonstrates that treatment with rHu Epo can markedly influence the course of tumor-induced anemia.

Literature review on the images of the nurse and nursing in the media

This study concentrates on the images of the nurse and nursing seen most commonly in the media and attempts to trace the images back to their origins and to explain their continued use, despite the rapidly changing role of the nurse in today's world. The images have been derived mostly from the historical roots of nursing and sometimes as a reaction to the increasing influence of the feminist movement. The author takes a look at the four main images of the nurse seen in the media, which are the ministering angel, the battleaxe, the naughty nurse and the doctor's handmaiden and then goes on to take a brief look at the other images commonly perpetuated by the media. The author summarizes the probable effects of the media stereotypes on nurses themselves and the service they provide and also takes a look at attempts to dispel these stereotypes.

Erythropoietin production in kidney tubular cells

The erythropoietin gene has been cloned in three mammalian species including man and recombinant erythropoietin is now used to treat the anaemia of chronic renal failure. Despite the isolation of the gene the precise cellular location of erythropoietin synthesis remains controversial. We present studies which demonstrate erythropoietin production by kidney tubular cells. Erythropoietin gene expression (messenger RNA) was detected by in situ hybridization using an oligonucleotide gene probe and the translated protein product by immunohistochemistry employing antibodies raised to pure recombinant DNA derived erythropoietin.

The metabolism of erythropoietin in the normal and uraemic rabbit

The metabolism of recombinant human erythropoietin (rHuEpo) labelled with 125I has been investigated in five normal and nine 5/6-nephrectomised rabbits. The plasma erythropoietin half-life was significantly prolonged at 5.1 +/- 1.2 h (mean +/- SD) in the 5/6-nephrectomised rabbits, compared to 3.0 +/- 0.4 h in sham-operated controls (P less than 0.001). The disappearance of 125I-labelled rHuEpo is biphasic. Examination of serum by fast protein liquid chromatography (FPLC) following administration of 125I-labelled rHuEpo by FPLC showed a single peak of radioactivity in all rabbits except two of the nephrectomised group. In serum from both of these animals a second labelled peak was found, corresponding to material of MW 200,000-250,000 D. We conclude that the 5/6-nephrectomised rabbit provides a stable model for the study of hormonal metabolism in chronic renal failure.

The effect of hypobaric hypoxia on misonidazole binding in normal and tumour-bearing mice

The effect of hypobaric hypoxia on the in vivo binding of misonidazole was investigated in normal mice and mice bearing T50/80 or CA NT mammary carcinomas. After the intraperitoneal injection of radiolabelled misonidazole, mice were randomised to breathe either room air or air at 0.5 atmospheres. The distribution of misonidazole in liver, kidney, heart, spleen and tumour tissue, 24 h later, was studied by scintillation counting and by autoradiography. Significantly higher misonidazole binding occurred in the livers (x2.5), kidneys (x2.4), spleens (x2.9) and hearts (x1.8) of hypoxic mice compared to controls. Hypobaric hypoxia was associated with a greater than four-fold increase in misonidazole binding within T50/80 tumours. However, significantly higher binding was not demonstrated within CA NT tumours after exposure of tumour-bearing animals to hypoxic conditions. In autoradiographs of hypoxic liver, labelling was intense in regions near to hepatic veins but sparse in areas surrounding portal tracts. This pattern was striking and consistent. In hypoxic kidney, labelling was most intense over tubular cells, less intense over glomeruli and sparse in the renal medulla. It is likely that the hepatic and renal cortical distributions of misonidazole binding reflect local oxygen gradients.

Serum erythropoietic activity in acute anemia--an animal model

Serum erythropoietic activity and reticulocyte response to anemia were investigated using a rabbit model. In hemolytic anemia, induced by injections of phenylhydrazine on Day 0 the hemoglobin reached a nadir (mean, 6.23 g/dl) on Day 4 when SEA was maximal (mean, 765 mU/ml). In animals venesected on Day 0 and Day 1 to produce anemia of equal severity, the SEA was maximal (mean 235 mU/ml) on Day 2. In both groups the reticulocyte response peaked on Day 7--at 34% for the hemolytic group and 21% for the venesected group. The 2,3-diphosphoglycerate, measured on Day 4, was significantly reduced in the PHZ-treated group. In the venesected group the 2,3-DPG increased between Day 0 and Day 4. There were no concurrent changes in acid-base balance. These results imply that the degree of anemia is only one of the factors which influence the level of circulating SEA.

Comparison of the mouse spleen cell assay and a radioimmunoassay for the measurement of serum erythropoietin

The mouse spleen cell assay (MSCA) has been compared with a radioimmunoassay for the measurement of serum erythropoietin (Ep). In 20 normal subjects the serum values ranged from 15 to 73 mU/ml for the MSCA compared with 5-30 mU/ml for the RIA. For normal sera there was no correlation between the results of the two assays. In 37 patients with anaemias of differing aetiologies and at various stages of treatment values ranged from 10 to 3645 mU/ml for the MSCA and 13-10,000 mU/ml for the RIA. Although patient values from the two assays were highly correlated (r = 0.98, P less than 0.001), the MSCA results were generally lower. These discrepancies can be largely accounted for by two factors. Firstly the MSCA is sensitive to non-specific matrix effects. Secondly, heat inactivation of serum, a prerequisite for the MSCA, but not for the RIA, destroys a variable and unpredictable proportion of the Ep in the test sera leading to an underestimation of Ep in the MSCA. We conclude that the RIA is more reliable than the MSCA which, in its present form, cannot be recommended for the accurate measurement of serum erythropoietin.

Red cell pyrimidine 5' nucleotidase deficiency: determination of nucleotidase activity and nucleotide content using HPLC

The hereditary deficiency of erythrocyte pyrimidine 5' nucleotidase has been investigated using an HPLC anion-exchange procedure designed to measure both red cell nucleotide content and enzymic activity. Red cell nucleotide profiles were determined using a low pH phosphate buffer salt-gradient system in 20 min, whereas a low pH buffer alone permitted the determination of enzymic activity with each of six different nucleotide substrates in less than 4 min. Both the red cell nucleotide profiles and the enzymic activity of haemolysates from two affected brothers and their children agreed well with previously published values. This unified approach should prove useful for detailed studies of deficiencies involving isoenzymes of pyrimidine nucleotidase.

Obtaining estimates of marginal cost by DRG

Marginal cost is the additional cost incurred for an additional unit of output. The importance of healthcare organizations knowing marginal costs in a DRG environment will increase due to greater competition and falling occupancy and payment rates. A method for obtaining estimates of marginal cost by DRG has been developed. This method is relatively inexpensive to apply, requires information from general accounting records and Medicare logs, and uses linear regression analysis.

Renal function in the elimination of oral melphalan in patients with multiple myeloma

Pharmacokinetic studies in 11 patients with multiple myeloma were undertaken on the first and last days of one course of chemotherapy. The drug was administered PO in single doses of 6-14 mg daily. Melphalan concentrations were determined by high-performance liquid chromatography. The interpatient variability of pharmacokinetic parameters noted by other authors was observed. Regression analysis showed a significant positive correlation between the elimination rate constant for melphalan and renal function (P = 0.003). The form of the line which describes the overall elimination rate constant for melphalan is given by the equation: Kel = 5.67 X 10(-3) + [4.90 X 10(-5) X GFR]. There was also a significant negative correlation between renal function and the area under the plasma melphalan concentration/time curve (P = 0.006). In vitro stability studies of melphalan in plasma at 37 degrees C and pharmacokinetic data suggest that hydrolysis and renal clearance are the major mechanisms of melphalan elimination. This work shows quantitatively the relationship between renal function and drug elimination and how the data may be used in predicting melphalan half-life from creatinine clearance.

Can food affect the bioavailability of chlorambucil in patients with haematological malignancies?

Pharmacokinetic studies in ten patients with haematological disorders were undertaken on the first and second days of one course of chemotherapy. Patients received chlorambucil under fasting and non-fasting conditions. Plasma concentrations of chlorambucil were determined by a reversed-phase high-performance liquid chromatography assay. Statistical analysis by the Wilcoxon signed rank test for non-parametric data indicated that food caused a significant reduction in peak plasma levels (P less than 0.01), elimination rate constants (P less than 0.01) and area under the plasma chlorambucil/time curve (P = 0.01). Food was also found to prolong the time taken to attain peak plasma levels (P less than 0.01). Regression analysis of renal function with elimination rate constants showed that chlorambucil elimination was independent of renal function (n = 8; r = -0.007; P = 0.72). In view of these results we suggest that chlorambucil is given on an empty stomach.

Lymphocytes from patients receiving lithium do not inhibit CFU-C growth

Lymphocyte subset levels and function were examined in 12 patients on lithium therapy and in 11 healthy hospital personnel. Co-culture of allogeneic human bone marrow cells with monocyte-depleted lymphocyte preparations revealed that CFU-C formation was significantly reduced (mean 43% inhibition) in the presence of normal lymphocytes but not with the patients' lymphocytes (less than 5% inhibition). This did not reflect numerical changes in lymphocyte subsets, since these were similar for control and lithium subjects. T colony formation was significantly depressed in the patient group (P less than 0.05), whereas B colony numbers were similar in both groups (P greater than 0.1). The possible role of HLA-incompatibility affecting CFU-C growth was investigated in co-culture experiments, using lymphocytes from HLA-identical twins, one of whom was receiving lithium. In four separate co-culture experiments, the inhibitory effect was shown with lymphocytes from the non-lithium twin but was not demonstrated by the lithium subject. Addition of lithium in vitro to co-cultures of normal marrow and lymphocytes was found to negate the inhibitory phenomenon in a dose-related manner. It is postulated that granulocytosis induced by the administration of lithium may be a manifestation of changes in a lymphocytic control system.

Enumeration of absolute numbers of T lymphocyte subsets in B-chronic lymphocytic leukaemia using an immunoperoxidase technique: relation to clinical stage

An immunoperoxidase technique has been used to identify and enumerate helper and suppressor T-cell subsets, as defined by reactivity with Coulter T4 and OKT8 monoclonal antibodies in 54 patients with B chronic lymphocytic leukaemia (B-CLL) and in the same number of matched controls. The ratio of T4+ to T8+ cells was significantly reduced in the B-CLL group as a whole (P less than 0.001) and in each stage of the three clinical staging systems. There was an increase in the median absolute level of T8+ cells in the whole CLL group (P less than 0.001). However, subdivision of the CLL group by clinical staging systems revealed a large group (28 patients) in which median T8+ cell levels were not raised and median T4+ cell levels were low (P less than 0.01). There was no significant decrease in T4+:T8+ ratio, increase in T8+ cells or decrease in T4+ cells with progression of clinical stage. Absolute numbers of E+ cells were significantly raised in all staging systems as were E+ T4- T8- cells (P less than 0.001). A significant alteration in either of these populations with progression of clinical stage was not present.

Increased plasma glycosidase and protease activity in uraemia: possible role in the aetiology of the anaemia of chronic renal failure

We have measured plasma N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30) and neuraminidase (EC 3.2.1.18) activities as markers of glycosidase activity and immunoreactive trypsin (EC 3.4.21.4) levels as a marker of proteolytic potential in the plasma of normal and uraemic subjects. The levels of all of these enzymes are significantly elevated in the plasma of uraemic subjects when compared to normal. We have postulated that the combined attack of glycosidases and proteases on erythropoietin will lead to fragmentation of this glycoprotein hormone with loss of activity. This may be a major contributory cause to the anaemia of chronic renal failure.

Separation of erythropoietic stimulators in severe anaemia using high performance gel permeation chromatography

Patients with various types of anaemia, but with comparable haemoglobin levels, show a wide range of serum erythropoietic activity. We have developed a method for the fractionation of serum by HPLC followed by bioassay of the individual fractions, using the mouse spleen cell microassay. Up to three distinct peaks of erythropoietic activity corresponding to molecular weights (MW) greater than 300,000, 250,000-300,000 and 40,000 have been found in serum from both normal and anaemic subjects. The erythropoietic profiles of the sera examined differ markedly in anaemias of different aetiology. The chemical nature and the physiological significance of the stimulators remain to be investigated.

The effect of transferrin saturation on the estimation of erythropoietin by the mouse spleen cell microassay

The effect of transferrin from various sources and the degree of saturation with iron on the stimulation of DNA synthesis by erythropoietin (Epo) has been investigated. Mouse, human, and bovine transferrins saturated with iron caused an increase in thymidine incorporation both in the absence and presence of Epo. In contrast, exogenous human and bovine apotransferrin resulted in significantly decreased incorporation of the tracer. The iron saturation of serum alters its apparent erythropoietic activity. This transferrin saturation effect may be overcome by a simple modification involving the addition of iron to the culture medium.

Acid hydrolase activities in B cell chronic lymphocytic leukaemia lymphocytes: correlation of cytochemical reactions with immunological phenotype

The cytochemical reactions of 5 acid hydrolases, alpha-naphthyl acetate esterase (ANAE), acid phosphatase (AP), beta-glucuronidase, beta-glucosaminidase and dipeptidylaminopeptidase IV (DAP IV) were investigated in lymphocytes from 30 patients with B cell chronic lymphocytic leukaemia (B-CLL). Based on ANAE and AP reactivities, 4 cytochemically distinctive subgroups were identified: Group 1: AP and ANAE less than 50% positive lymphocytes (5 cases); Group 2: AP greater than 50%, ANAE less than 50% positive lymphocytes (11 cases); Group 3: AP less than 50%, ANAE greater than 50% positive lymphocytes (7 cases); Group 4: AP and ANAE greater than 50% positive lymphocytes (7 cases). beta-Glucuronidase displayed similar patterns of reactivity to AP. beta-Glucosaminidase activity was observed in the majority of lymphocytes in most patients, whereas DAP IV activity was present in less than 20% of lymphoid cells. The study failed to establish any relationship between cytochemical grouping and patients' clinical status, peripheral lymphocyte counts, E or mouse rosette values, light or heavy chain cellular immunoglobulin (Ig) class. Attempts to correlate acid hydrolase and Ig heavy chain isotype expression, putative markers of B cell maturation, were unsuccessful and indicate that within the narrow spectrum of B cell differentiation seen in B-CLL these characteristics are unrelated.

Depletion of T-lymphocyte subsets using monoclonal antibody and complement: effect on T-colony formation

Using monoclonal antibody and fresh rabbit serum, mononuclear cells from 11 healthy individuals were depleted of either helper or suppressor T-lymphocytes by complement-mediated lysis. The effect on T-lymphocyte colony formation was studied to determine the nature of the T-colony-forming cell. While depletion of either subset of T-lymphocytes significantly reduced T-colony formation compared to controls (P less than 0.01), colony formation did not differ significantly between helper or suppressor T-cell-depleted cells. Thus T-colony formation appears to be a property of both helper and suppressor T-lymphocytes, and both subsets are necessary for optimal colony formation.

Dipeptidylaminopeptidase IV activity in normal and leukemic T-cell subpopulations

Dipeptidylaminopeptidase IV (DAP IV) cytochemical reactivity was investigated in monoclonal antibody defined T-lymphocyte subpopulations from normal blood and in cells from a series of T-cell leukemias of defined immunologic phenotype. A combined monoclonal antibody/immunocolloidal gold technic, which enabled simultaneous visualisation of immunogold label and DAP IV reactivity, was used to study enzyme reactivity in normal T-cell subpopulations. Single or several discrete granules of DAP IV reaction product were observed in 72% of OKT3+ and OKT4+ cells, whereas a significantly (P less than 0.01) lower percentage of OKT8+ cells (41%) displayed positivity; B-cells were invariably DAP IV negative. In the T-cell leukemias, DAP IV reactivity was strongest in T-lymphoblastic lymphoma and T-prolymphocytic leukemia cells. In contrast, DAP IV activity was absent or expressed in a minority of cells of the more immature T-acute lymphoblastic leukemia. The enzyme reaction also was negative in lymphocytes from other mature T-cell leukemias: T-chronic lymphocytic leukemia (OKT8+), adult T-cell lymphoma-leukemia, and Sezary syndrome (both OKT4+). DAP IV expression did not parallel that of acid phosphatase or alpha-naphthyl acetate esterase in leukemic T-lymphoid cells except in T-lymphoblastic lymphoma and T-prolymphocytic leukemia, where a strong reaction with the three hydrolytic enzymes was observed.

An evaluation of three statistics of structured exploratory data analysis

The power of structured exploratory data analysis (SEDA) to discriminate among major genic, polygenic, and nongenetic determination of phenotypes was investigated using computer simulation. Three classes of SEDA indices (the major gene index, the offspring between parents function, and the midparent-child correlation coefficient) were evaluated. These three statistics, in combination, were reasonably sensitive in detecting the presence of a major locus and in discriminating between phenotypes with genetic effects and those with no genetic component. However, they were unable to discriminate between major genic and polygenically determined phenotypic models.

Human umbilical cord conditioned medium: a stimulus for human CFU-G

Segments of human umbilical cord have been used to prepare a highly active conditioned medium (HUCCM) for in vitro human granulopoiesis and have been compared with human placenta conditioned medium (HPCM) and feeder layers. The HUCCM produced more colonies on day 7 than HPCM (P less than 0.001), and colonies consisted almost exclusively (over 98%) of granulocytic cells by both morphological and cytochemical analysis. The HUCCM-stimulated colonies have a short culture life, the number of colonies being maximal on day 7 of culture with few colonies remaining on day 10. The main source of the colony-stimulating activity in the umbilical cord was found in the Wharton's Jelly component.

Metabolism of exogenous adenine in a pyruvate kinase-deficient patient

The metabolism of adenine, administered intravenously and orally, was studied in a patient with red cell pyruvate kinase (PK)-deficiency. Intravenous infusion of 58.5 mumol of adenine per kg containing 6475 Bq of 8-14C adenine caused an initial decrease in red cell ATP level and the gradual return to the pre-infusion level coincided with an increase in radiolabelled ATP. Of the infused adenine, 1.3% had entered the red cell pool after 2 h. The route of administration affected the urinary excretion of adenine and its oxymetabolites; after 6 h, 10.7% of the infused adenine had been excreted, compared with 7.4% after ingestion of a similar dose. In 10 control subjects given 45.1-55.5 mumol/kg, excretion of adenine plus oxymetabolites accounted for 13.5 +/- 2.9% of the ingested dose. Differences were also observed in the urinary purine excretion patterns for the two routes of administration. This study has shown that adenine can be incorporated into ATP in the red cells of a PK-deficient patient.

Pharmacokinetics of low-dose methotrexate in children receiving maintenance therapy for acute lymphoblastic leukaemia

Serum methotrexate (MTX) concentrations were measured by immunoassay in 28 children receiving maintenance therapy for acute lymphoblastic leukaemia. Patients were studied either after a single weekly dose or on the first day of a 5-day course of treatment. A standard dose (15 mg/m2) was given PO and/or IV. After PO dose the peak serum MTX concentration and its timing varied widely between cases and there was a significant positive correlation between the rate of serum concentration rise and the area under the concentration curve up to 4 h. The absorption rate constant showed a biphasic distribution and correlated less closely with early serum concentrations. After IV and PO administration drug disposition was triphasic with an initial rapid distribution phase, an intermediate phase, and a prolonged terminal elimination phase. The intermediate phase half-life was significantly longer after PO than after an IV dose. The MTX clearance rate was consistently lower than the glomerular filtration rate and there was no significant correlation between the two. The mean bioavailability (PO/IV) was 42%, but bioavailability was as low as 6% in some cases due to prolonged high serum concentrations after an IV dose, which was not seen with the equivalent PO dose.

The pharmacokinetics of vincristine in man: reduced drug clearance associated with raised serum alkaline phosphatase and dose-limited elimination

A radioimmunoassay has been used to investigate the pharmacokinetics of vincristine in 39 cancer patients who received between 0.4 and 1.54 mg vincristine/m2 as part of standard treatment protocols. There was wide interindividual variation in both the terminal elimination half-life of vincristine (t1/2beta) and the associated volume of distribution (Vd), resulting in an 11-fold range of dose-corrected area under the plasma concentration versus time curve values (AUC0-infinity). Elevated vincristine AUC0-infinity values were observed in those patients with raised serum alkaline phosphatase at the time of vincristine estimation. The t1/2beta was significantly longer in these patients than in those with serum alkaline phosphatase within normal limits, suggesting that biochemical evidence of cholestasis is associated with reduced clearance of vincristine. Evidence is also presented to suggest that the clearance of vincristine is dose-dependent within the therapeutic dose range. We observed a disproportionate rise in vincristine plasma concentration at doses exceeding t1/2beta compared with that observed for patients receiving 1 mg vincristine/m2 or less.